I have an 04 ls. The cat has been cut off and the exaust is open. Is it safe to drive until i can buy a cat or will it harm my vehicle. What are the consequences of running open exaust other than the noise?
Well, I did OPEN HEADER for a hundred miles or so and due to the lack of backpressure, I lost power and ran RICH (but I was tuned at the time) and that means my MPG went down big time but again who cares about MPG when you wanna be fast - this case I did care because normal driving made me run rich. Does it harm the motor? If you run Rich, the plugs etc. get ruined quick. Will you do more damage than that, I don't think so but I'll let the GURUs on here answer that.
"FRIENDS DON'T LET FRIENDS DRIVE STOCK"
02ECOTECIMPORTKILLER wrote:Well, I did OPEN HEADER for a hundred miles or so and due to the lack of backpressure, I lost power and ran RICH (but I was tuned at the time) and that means my MPG went down big time but again who cares about MPG when you wanna be fast - this case I did care because normal driving made me run rich. Does it harm the motor? If you run Rich, the plugs etc. get ruined quick. Will you do more damage than that, I don't think so but I'll let the GURUs on here answer that.
Not trying to be a dick, but can you please stop using the word "backpressure" to infer that it is necessary to make horsepower on any motor? You're teaching people the wrong idea. What you're meaning to say is that exhaust piping, especially in N/A applications, needs to be a certain size to promote the correct exhaust gas velocity and scavenging effect. These things, when correct, help to pull the exhaust gasses out of the head and through the exhaust piping. With a wide open exhaust or piping that's way too big, the exhaust is moving much slower as it's leaving the motor. Picture it like a garden hose with your thumb over it.; the water moves much slower with no restriction.
To OP, you'll probably be ok. It'll be extremely obnoxious and it will throw a check engine light; likely for the oxygen sensor named Bank 1, Sensor 2 (B1S2). It will probably run rich, like mentioned above. So, don't expect stellar fuel mileage or performance during this time. There's always the slight possibility of burning a valve but since these motors come with stainless valves that risk is reduced.
"In Oldskool we trust"
Not being a dick at all man. Thanks for the correction - it is a term that I see used a lot and so it has become part of my mechanical vernacular. Is it the same if the exhaust piping is too big; gas velocity is decreased, reducing performance, running rich etc?
"FRIENDS DON'T LET FRIENDS DRIVE STOCK"
All but the running rich part. That will be a function of his upstream oxygen sensor seeing fresher air than normal.
"In Oldskool we trust"
Running open headers can ruin valves. But open cat your fine like others said might lose power and mpg. Plus make sure exhaust isn't blowing on rear o2 might damage it if melts wires. And will be very loud.
Very true about the valves, forgot about that. Stainless steel valves have less of a chance to bend but....didn't happen to me and I was redlining all the time
"FRIENDS DON'T LET FRIENDS DRIVE STOCK"
